Ability to iterate over webassembly contents with JS api

[hummeleBop]

The Js api can't be used to iterate over WebAssembly functions and exports.
This feature could be really useful.

For now, to get a function, we need, at least, to know its name.

[ Edit: In a more general way, binaryen (via its js wrapper) could be able to list the exports, the data sections, the globals and all the functions. ]

[brmorr]

As a workaround, you can print to WAT and then regex as needed. I am doing this now to generate a list of all function names. +1 on adding this directly to the JS API.

[COFFEETALES]

Partial solution in the following commit:
29da5c9

[RReverser]

Sounds like @dcodeIO is working on porting #2386 to JS - is that correct?

This API would be extremely useful, as right now there is no way to perform transformations on code anywhere in the module.

[bvibber]

The accessors in #2386 have landed, but the npm module doesn't seem to have updated if I install as npm install binaryen. If I install a nightly build with npm install binaryen@nightly it gives a current build which includes them.

I did find a bug in the handling of switch destination label names, for which I have a fix in #2553. Otherwise seems to be enough to both list out the functions and walk through the code in the function bodies.

[dcodeIO]

For a bit of background: The latest tag of the npm package updates with new version_XY tags on the main repo. I guess there hasn't been a tag since the updates, so these features are only available in the nightlies so far.

[kripken]

I tagged version 90 now.

[dcodeIO]

Reporting back from the buildbot: There's a v90.0.0 now with updated definitions and docs, that also ships the (yet undocumented) Wasm variant as const binaryen = require("binaryen/wasm");. The Wasm variant requires awaiting the binaryen.ready promise.

[bvibber]

Awesome, thanks!

I've got most of what I seem to need for iterating over things now on my project, except for iterating through the function table initialization segments. I'll try and put together a patch later adding that if I can work it out.

[bvibber]

Also would be useful to iterate over globals; as a workaround I can find all the ones that are referenced in a get/set or an export.